Jesse Jackson Jr. has depression. What is that, exactly?

The CDC’s most recent estimate says about 1 in 10 U.S. adults have some form of depression, a treatable mental illness that can range in severity from mild to major. The National Institute of Mental Health (NIMH) estimates that more than 6 million men in the U.S. have depression each year. Among those most likely to meet the criteria for major depression, according to the NIMH, are blacks and people ages 45 to 64. Jackson, who is black, is 47 years old.

Increased stress, chronic or acute, poses a depression risk, Cochran says, as does loss – “a relationship breakup, death of a family member or friend, the loss of a job.” A family history of depression increases one’s risk; so do alcoholism and substance abuse.

According to the NIMH, symptoms can include persistent sadness or anxiety, an “empty” mood, loss of interest or pleasure in hobbies or activities, difficulty sleeping, difficulty concentrating, restlessness and thoughts of suicide.

“There’s a wide variety of severity,” Cochran says. “Many people muster on and live with chronic low mood over a period of time. But for those with moderate or severe depression, it may be harder to get up and just keep going” every day.

Treatments for depression include cognitive and behavioral therapies, typically administered by a psychologist, and antidepressant medications, which require a prescription from a psychiatrist or other M.D. (Read here about a less commonly used magnetic-stimulation treatment that may help those whose depression has resisted more traditional treatment approaches.)

Cochran says that both behavioral and drug treatments have proven “just as effective with men as with women.” But for reasons not fully understood, men tend to seek treatment at far lower rates than women do. “What we have [in the way of treatment] works,” Cochrane says. “It’s one of the success stories of the past 50 years, the way psychology and psychiatry have refined treatments for depression.”

But “how to get men to get help” is “a real challenge,” Cochrane notes. “They seek help at about half the rates of women.”

“The theory is that it’s so ingrained for men not to seek help in our culture,” Cochrane says. “Even to this day, we’re sending messages about being tough and not relying on others.” Many men apparently opt to “suck it up,” instead of seeking treatment. “They can grind away and get worse and worse, until they get into a life or death situation and need major intervention” at a hospital or residential treatment center, Cochrane notes.

To encourage men to acknowledge depression and get treatment if they need it, the NIMH in 2003 launched its “Real Men. Real Depression.” campaign, in which everyday-Joe kinds of men share their experiences with depression. Cochrane says the effort has had a “strong effect” on men’s seeking treatment. The campaign, Cochrane observes, suggests “how wimpy it is not to get help.”